BARBADOS-ANTIGUA REPORTS 47 
Spirobranchus giganteus Pallas 
Plate VI, Figs. 6, 7, and 8 
This is a relatively large specimen 75 mm. long, including 
the branchie, 9 mm. wide in the thoracic region, and tapering 
posteriorly. The body, which is divided into thorax and abdo- 
men, is oval in cross-section. On each side of the thorax, which 
is divided into 6 segments, there are 6 bundles of sete, located 
just above the thoracic membrane. The sete on the collar are 
of two kinds, which differ only in length and in degree of curv- 
ature. The longer ones are slightly bent; the shorter ones are 
strongly curved. The thorax is also provided with an undu- 
lated membrane on each side, employed chiefly in smoothing 
the inside of the tube. This is a modification of the cirri. The 
shield glands are confined to this region. The branchie, which 
are 15 mm. in length, are in two bundles, each having 5 whorls. 
The branchial filaments are numerous and are situated on a 
broad base. The peduncle is large, wide, but thin. Its edges 
are almost cutaneous and protrude like wings so that the 
branchiz can be withdrawn into them. The operculum is plate- 
shaped, and out of its depression arise two large antler-like 
processes and two smaller horn-like processes. The former ex- 
tend outward and have several sharp prongs; the latter have 
three small teeth near the tip. This operculum is a modifica- 
tion of two of the branchial filaments. The collar is ruffled and 
is divided by the ventral groove into two symmetrical lobes, 
each of which bears a chalky-white spot. 
This animal builds a convoluted caleareous tube, smooth and 
poreelain-like within. The interior is a deep lavender, shading 
to white at the rim. The colors of the animal itself are very 
striking. The branchiz and antlers are deep carmine red; the 
operculum is yellow; and the body of the worm is flesh-colored. 
Contrasted with the white tube, this highly-colored annelid is 
decidedly showy. When disturbed, it quickly withdrawns into 
its dwelling. A number of specimens were found with tubes 
attached to the links of an old anchor-chain in English Harbor. 
Prof. A. O. Thomas kindly assisted in the work of collecting 
these specimens; but it was impossible to secure any perfect 
tubes, because they are curved and were so solidly cemented 
